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47dba7ba26
When rbd_do_request() has a request to process it initializes a ceph file layout structure and uses it to compute offsets and limits for the range of the request using ceph_calc_file_object_mapping(). The layout used is fixed, and is based on RBD_MAX_OBJ_ORDER (30). It sets the layout's object size and stripe unit to be 1 GB (2^30), and sets the stripe count to be 1. The job of ceph_calc_file_object_mapping() is to determine which of a sequence of objects will contain data covered by range, and within that object, at what offset the range starts. It also truncates the length of the range at the end of the selected object if necessary. This is needed for ceph fs, but for rbd it really serves no purpose. It does its own blocking of images into objects, echo of which is (1 << obj_order) in size, and as a result it ignores the "bno" value returned by ceph_calc_file_object_mapping(). In addition, by the point a request has reached this function, it is already destined for a single rbd object, and its length will not exceed that object's extent. Because of this, and because the mapping will result in blocking up the range using an integer multiple of the image's object order, ceph_calc_file_object_mapping() will never change the offset or length values defined by the request. In other words, this call is a big no-op for rbd data requests. There is one exception. We read the header object using this function, and in that case we will not have already limited the request size. However, the header is a single object (not a file or rbd image), and should not be broken into pieces anyway. So in fact we should *not* be calling ceph_calc_file_object_mapping() when operating on the header object. So... Don't call ceph_calc_file_object_mapping() in rbd_do_request(), because useless for image data and incorrect to do sofor the image header. Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Josh Durgin <josh.durgin@inktank.com> |
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| .. | ||
| aoe | ||
| drbd | ||
| mtip32xx | ||
| paride | ||
| xen-blkback | ||
| amiflop.c | ||
| ataflop.c | ||
| brd.c | ||
| cciss_cmd.h | ||
| cciss_scsi.c | ||
| cciss_scsi.h | ||
| cciss.c | ||
| cciss.h | ||
| cpqarray.c | ||
| cpqarray.h | ||
| cryptoloop.c | ||
| DAC960.c | ||
| DAC960.h | ||
| floppy.c | ||
| hd.c | ||
| ida_cmd.h | ||
| ida_ioctl.h | ||
| Kconfig | ||
| loop.c | ||
| Makefile | ||
| mg_disk.c | ||
| nbd.c | ||
| nvme.c | ||
| osdblk.c | ||
| pktcdvd.c | ||
| ps3disk.c | ||
| ps3vram.c | ||
| rbd_types.h | ||
| rbd.c | ||
| smart1,2.h | ||
| sunvdc.c | ||
| swim3.c | ||
| swim_asm.S | ||
| swim.c | ||
| sx8.c | ||
| ub.c | ||
| umem.c | ||
| umem.h | ||
| virtio_blk.c | ||
| xd.c | ||
| xd.h | ||
| xen-blkfront.c | ||
| xsysace.c | ||
| z2ram.c | ||